Power shovel



Mar. 6, 1923.

.E. 'J. [ARMSTRONG POWER SHOVEL original Filed om. so, 1919 2 sheets-sheet 1 Mar. 6, 1923.

1,447,332 E, J! ARMSTRONG POWER SHOVEL iginal Filed Oct. 50, 1919 2' sheets-sheet 2 Patented Mar. 6, 1923.

LMMBZ PATENT @iFlQE.

EDWIN J'. ARMSTRONG, OF ERIE, PENNSYLVANIA, ASSIGNOR TO BALL. ENGINE COM- PANY, OF ERIE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

POWER SHOVEL.

Original application filed October 30, 1919, Serial No. 334,515. Divided and this application filed October T 0 aZZ whom it may] 0071 cam.

Be it known that I, EnwlN J. ARMSTRONG, a citizen of the United States, residing at Erie, in the county of Erie and State of Pennsylvania, have invented new and use ful Improvements in Power Shovels, of which the following is a specification.

This application is a division of application #334,515 filed by me Oct. 30th, 1919, for improvements in power shovels.

In the use of power shovels it is necessary to raise and lower the boom. This is made necessary sometimes by reason oi the condition of the work.

Other times it is necessary to lower the boom in order that it may clear obstructions in the moving of the shovel from place to place. It is desirable that the support for the boom tend to brace the boom against edgewise movement. In the ordinary shovel also the. cab is so formed'that when the boom is raised to its upper position it occupies an opening in the cab root. lVhere this is done it is desirable to have the support extend through the same opening when the boom is lowered. Further it is desirable to have this raising and lowering of the boom accomplished with as little effort as possible and from a convenient position in the cab;

The invention is illustrated in the accompanying drawings as follows Fig. 1 shows a side elevation of a power shovel.

Fig. :2 a plan view of the shovel.

Fig. 3 an end view of the step by step mechanism for actuating the reel for the boom support.

Fig. 4 is a side elevation, partly in section, of said step by step mechanism, the mechanism being set for lowering the boom.

1 marks the truck frame, 2 the wheels, 3 the annular bed, 5 the platform which is carried on the bed by means of rollers 1, and 5 the usual cab on the platform.

A strut 6 extends upwardly from the platform to a point slightly above the roof 5 and has a tension rod or brace 7 extending therefrom to a portion of the frame. Ordinarily there are two of these struts arranged some distance apart. A boom 8 is hinged at S- 011 the platform 5 in the usual manner.

An excavating device or shovel 9 in the par-- ticular exemplification shown is carried by a dipper stick 10 and is operated through the Serial No. 509,946.

lines 11 which extend over a pulley 12 at the end of the boom to the usual operating mechanism (not shown) on the platform.

A reel 15 is journaled at the upper ends of the strut 6 and flexible supports in the form of cables 16 extend from the reel over pulleys 17 at the sides of the boom at its forward end and the cables are anchored at the upper ends of the strut 6. The root 5* is provided with a slot 18. The sides of the slot are faced for a slight distance at 19 and the rear end of the slot is covered by a closure 19*. This slot permits the full movement of the dippersticlrwhen in a horizontal position.

When it is desired to raise the boom, this is accomplished by winding up the cable on the reel 15. lVhen it is desired to lower the boom the cable is unwound from the reel 15 allowing the boom to drop. As the boom is lowered the cable, or support 16 is carried to the position that it would contact the edge of the roof 5 it it were not that the cables at each side were brought closely enough together by the unwinding of the cable from the reel to allow them to extend into the slot 18. To facilitate this same clearance the spans of cable leading over the pulleys 17 to the anchors at the upper end of the strut are usually temporarily bound together so as to afford this clearance by lashing 16. In order to accomplish this rolling in or the cable it will be understood that the cable is secured to a. projection l5 on the reel at the center and as it is wound up the spans of cable are carried on the reel so that when the boom is in ordinary working condition the supports for the cables 16 on the reel are separated, thus bracing to some extent the boom.

In order to conveniently lift and lower the boom the reel 15 is provided with a step by step operating mechanism, the lever for actuating which extends down into the cab of the machine. These devices must necessarily be very powerful to carry the load of the boom and attached parts and at the same time must be capable of both raising and lowering the boom with perfect safety. I have shown such mechanism as follows: The reel 15 is in the form of a sleeve and journaled in the rod 15, the rod 15 being secured to the upper ends of the struts. A ratchet wheel 20 is fixed on the end of the reel 15. A pawl carrier 21 is mounted on the rod 15 and a bracket 21 which extends from the strut 6. A pawl lever 22 is pivotally mounted on the carrier 21 by means of a pin '22. A link 23 is pivotally connected with the lever 22 by means of a pin 24 and with an operating lever 26 by means of a pin 25. The operating lever is pivotally mounted on a bracket 28 by means of a pin 27. A pawl 29 is pivotally mounted on the pawl lever 22 by means of a pin 30 and is adapted to operate against the teeth 31 on the ratchet wheel 20. The pawl 29 thus forms the swinging pawl. A spring 32 pulls the pawl toward or into engagement with the ratchet wheel. A pawl 33 is pivotally mounted on the pin 22. It, therefore, has a fixed pivotal support. An arm 34 extends from this pawl and a spring 35 extends from the arm 34 to a part of the pawl carrier 21. The spring swings the pawl 33 into engagement with the ratchet 20 so as to lock the ratchet against unwinding as the pawl 29 is retracted after being advanced. By observing the parts as shown in Fig. 4 the operation of the step by step mechanism for the winding up operation is made clear. As the operating lever 26 is reciprocated the pawl lever 22 is reciprocated, reciprocating thepawl 29 and .thus advancing tooth by tooth the ratchet wheel 20, the ratchet wheel being caught and held against a return movement by the pawl 33.

In orderthat the step by step mechanism may be utilized for releasing the support, that is, unwinding the reel under load it is provided with the following mechanism A disengaging finger or dog 36 is provided on the pin 22 and has an arm 37 from which extends a spring 38. The spring 38 is carried by a lever 39, the lever being pivoted on a pin 40 in the pawl carrier. The lever has an extension or arm 41 to which a link 42 is attached by a pin 43. The link 42 is connected by a pin 44 with an arm 45. The arm 45 is pivotally mounted by a pin 46 on the bracket 28. A link 47 extends from the pin 44 to a grip lever 49, the link being connected to this lever by means of a pin 48. hen the grip lever is swung to the position shown in Figs. 5 and 6 the pin 44 is brought approximately to the center of the pin 27 so that the link 42 remains stationary as the operatinglever is operated.

The releasing mechanism operates as follows: It will be noted that as the link 42 is pulled down through the grip lever 49, the spring 38 is put under tension- The spring 38 is stronger than the spring 35. The release dog 36 is under the influence of the spring 38 and operates against the pawl 33 so that when there are no other agencies in action the release dog operating under the influence of the spring 38 will overcome the spring 35 and move the pawl 33 out of the path of the ratchet, the position assumed under these conditions being shown in Fig. 4.

The pawl 29 has a release finger 51 which extends into the path of the release dog 36.

The spring 38 with the leverages provided exerts a preponderance of pressure over the sprmg 32 or spring 35 as the case may be so that when the parts are not otherwise eflected the spring 38 ,will force the dog 29 through the dog 36 and release finger 51 to a position which will clear the ratchet teeth 31 or the ratchet 20. The details of this step by step operation form the subject matter of the application of which this is a division.

What I claim as new is 1. In a power shovel, the combination of a shovel platform having a cab thereon with a slotted roof; a boom pivotally mounted on the platform; a reel mounted on the platform; two flexible supports extending from the boom. to the reel and through the slot in the roof as the boom is lowered; and means for winding the supports on the reel, the

winding of the supports on the reel bringing the supports toward each other as the boom is lowered to reduce the clearance required in this slot for the two supports as the boom is lowered.

2. In a power shovel, the combination of a shovel platform having a cab thereon with a slotted roof; a boom pivotally mounted on the platform; a dipper stick 011 the boom adapted to be swung into the slot; a reel mounted above the roof; two flexible supports extending from the boom to the reel; and means for operating the reel to wind the supports, the winding spreading the supports as the boom is raised and bringing them toward each other as the boom is lowered to permit them to enter the slot.

In testimony whereof I have hereunto set my hand.

EDWIN J. ARMSTRONG. 

